Abstract
In many European Countries, there are bioethanol storage depots, which are often subjected to Seveso Directive. Indeed, accidental bioethanol releases can be hazardous, because its evaporation from pool can generate potentially explosive atmospheres. In bioethanol production plants or storage depots, there are several components (flanges, valves, pumps, etc.), which can become potential emission sources in case of failure. In accordance with Atex Directive 99/92/EC, the employer is obliged to carry out the classification of workplaces, where explosive mixtures could be generated. International Standard IEC EN 60079-10-1 is generally used to classify the hazardous zones due to the possible presence of potentially explosive atmospheres. The Standard reports the parameters, which have to be determined in order to classify the areas. In particular, the dilution degree is a required parameter for classifying the zone (hazardous or non-hazardous) generated by the potential source. In case of flammable liquids releases, such as bioethanol, this parameter is strongly dependent on evaporation rate. The paper reports the results of bioethanol evaporation study from pool by a specific software, which is able to predict the trend of evaporation rate, pool size and temperature as function of time. The chosen software is diffusely used to assess the accidents outcomes in plants subjected to Seveso Directive. With reference to evaporation from pool, the wind velocity influence on evaporation rate has been investigated. Indeed, the wind velocity is a very important parameter for studying the evaporation of high-boiling flammable liquids, such as bioethanol.
